The invention relates to methods and devices for treating skin.
Skin tissue consists of an outer epidermal layer overlying a dermal layer that is in contact with a layer of subcutaneous adipose tissue. Massaging of the skin has long been known to improve the blood circulation in the subcutaneous adipose tissue. Various types of massaging devices have been used for treating adipose tissue. U.S. Pat. No. 5,961,475 discloses a massaging device in which negative pressure is applied to the skin together with massaging. The combined treatment increases the blood circulation in the subcutaneous adipose tissue and breaks connections between adipose cells in the tissue.
U.S. Pat. No. 6,273,884 to Altshuler et al. discloses simultaneous application of optical energy and negative pressure to the skin in order to treat a skin defect.
The present invention is based upon the finding that skin heating improves skin elasticity and oxygen dissociation from hemoglobin in the blood. Improved skin elasticity allows more aggressive massaging of the skin and oxygen dissociation from hemoglobin causes fat destruction. In order to obtain these beneficial effects of heating on subcutaneous adipose tissue, it is necessary to conduct heat applied to the skin surface into the skin tissue to a depth of about 1 cm without damaging the skin.
The present invention is also based upon the findings that deforming a region of skin so that the region protrudes out from surrounding skin enhances heat delivery to the subcutaneous adipose tissue and cartilage.
In accordance with the invention, a region of skin to be treated is deformed so that the region protrudes out from surrounding skin, and radio-frequency (RF) energy is applied to the protrusion by applying one or more RF electrodes to the skin surface. In a preferred embodiment, the region of skin is deformed by applying a negative pressure to the region of the skin. Applying negative pressure to skin also increases the blood circulation in the skin. The skin surface can be hydrated to improve electrode coupling.
The RF electrodes may optionally be used to monitor skin impedance during the treatment. Since increasing skin temperature leads to a change in impedance, monitoring the skin impedance allows the temperature distribution in the skin to be followed so that the parameters of the treatment (intensity of the pressure or the RF energy) may be altered to optimize the treatment.
Thus, in a first aspect of the invention there is provided a method for carrying out a treatment of skin, comprising, for each of one or more regions of the skin:
(a) deforming the skin so that the region of skin protrudes from surrounding skin;
(b) applying radio frequency (RF) energy to the skin.
In a further aspect of the invention there is provided a system for treating skin, comprising:
(a) a skin deformer deforming the skin so that a region of skin protrudes out from surrounding skin; and
(b) one or more RF electrodes configured to apply RF energy to the skin.